The present disclosure relates to an image forming apparatus including an attachable/detachable intermediate transferring unit.
A full color image forming apparatus of recent years generally has a tandem-type configuration. In the tandem-type configuration, an image forming part provided for each toner color is disposed along a traveling direction of an endless intermediate transferring belt. In each image forming part, a single-color toner image is sequentially first-transferred onto the intermediate transferring belt to form a full-color toner image, and the full-color toner image is second-transferred onto a sheet. When the single-color toner image is transferred from each image forming part onto the intermediate transferring belt, a high voltage transferring bias is applied from a transferring bias power source to a first transferring roller which is disposed inside of a hollow space of the intermediate transferring belt so as to oppose to each image forming part.
The intermediate transferring belt and the first transferring rollers are united into an intermediate transferring unit. For the purpose of replacement or maintenance of the intermediate transferring belt or the first transferring roller, the intermediate transferring unit is configured to slide along a rail provided in an apparatus main body so as to be attachable to or detachable from the apparatus main body. The intermediate transferring unit is provided with a fixed contact point electrically connecting to the first transferring roller. On the other hand, the rail is provided with a movable contact point electrically connecting to the transferring bias power source. When the intermediate transferring unit is slid along the rail to be attached to the apparatus main body, the fixed contact point and the movable contact point are electrically connected to each other and a transferring bias is applied from the transferring bias power source to the first transferring roller.
In a case where the fixed contact point is provided in the intermediate transferring unit and the movable contact point is provided in the rail as described above, when the intermediate transferring unit is slid along the rail, there may be a case in which the movable contact point is hooked by the intermediate transferring unit or a frictional force between the movable contact point and the fixed contact point is too strong. In such a case, the movable contact point may be spaced away from the rail or the position of the movable contact point may be changed and then a contact failure between the movable contact point and the fixed contact point may occur.
In addition, there may be a case in which a plate-shaped movable contact point is provided in the intermediate transferring unit and the fixed contact point is provided in the rail. The movable contact point and the fixed contact point are disposed to oppose to each other in a vertical direction. One end portion of the movable contact point is fixed to the intermediate transferring unit and the other end portion is folded to form an engaging claw. Then, by engaging the engaging claw with an anti-folding member formed in the rail, the buckling of the engaging claw is prevented.